Temperature-dependent crystal structure investigation of 4f hybridized thermoelectric clathrate Ba8 – xCexAuySi46 – y

In this study, Ce was successfully substituted for Ba on the guest atom sites in the type-I clathrate Ba8 – xCexAuySi46 – y and the material was characterized using high-resolution synchrotron powder X-ray diffraction data measured from 100   K to 1000   K to investigate potential structural implications of the inclusion of a 4f element. The thermal expansion and bonding of the host structure are not affected by the presence of Ce, as seen from the linear coefficient of unit-cell thermal expansion of 7.30   (8)   ×   10 − 6 K − 1 and the average host Debye temperature of 404   (7)   K determined from the multi-temperature atomic displacement parameters, both of which are similar to values obtained for pure Ba8AuySi46 – y. The anisotropic atomic displacement parameters on the guest atom site in the large clathrate cage populated by Ba surprisingly reveals isotropic behavior, which is different from all other clathrates reported in literature, and thus represents a unique host – guest bonding situation.

Source: Acta Crystallographica Section B - February 22, 2022 Category: Chemistry Authors: Sandemann, J. Reardon, H. Brummerstedt Iversen, B. Tags: thermoelectrics synchrotron powder diffraction atomic displacement parameters Debye and Einstein temperatures clathrates research papers Source Type: research